1. Field of the Invention
The present invention relates to an optical disc recording/reproducing apparatus for recording information to an optical disc and reproducing information recorded on the optical disc, and particularly relates to recording control and reproduction control for an optical disc of DVD+R type.
2. Description of Related Art
In recent years, there has been a wide spread of DVDs (Digital Versatile Disc) as an optical disc capable of recording a large amount of video/audio data that of movies or the like. As these DVDs, various types are known such as a DVD-ROM containing information that is pre-recorded by a manufacturer and can not be rewritten by a user, a DVD-R or a DVD+R that allows the user to record information thereon only once, and a DVD-RW, a DVD+RW, or a DVD-RAM that allows the user to rewrite information thereon repeatedly. Information recorded on these DVDs can be reproduced by optical disc reproducing apparatuses (DVD players) or optical disc recording/reproducing apparatuses (DVD recorders), and information can be recorded on a DVD-R, a DVD+R, a DVD-RW, a DVD+RW, and a DVD-RAM by using optical disc recording/reproducing apparatuses (DVD recorders).
Here, among these types of optical discs, a description will be given of the conventional recording control and reproducing control for the DVD+R optical disk.
First, a description will be given of the recording control for the DVD+R optical disc performed by a conventional optical disk recording apparatus. When a DVD+R  optical disc is inserted in the apparatus and loaded therein (mounting process for reading out disc information), the optical disc is detected as a DVD+R optical disc. Then, recording on the DVD+R optical disc begins in +VR mode in response to recording key operation on a remote control unit or the preset time to begin the recording when the programmed recording (programmed video recording) is activated.
In this way, the recording on the optical disc begins, and the information to be recorded first is then recorded as a title T1 in the data area of the optical disc. When the title T1 has been recorded, an RSAT (Reserved Space Allocation Table) that indicates title information of the title T1 is recorded after the title T1. Then, information to be recorded next is recorded as a title T2 in the data area of the optical disc. When the title T2 has been recorded, an RSAT that indicates title information of the title T2 is recorded after the title T2. Further, information to be recorded next is recorded as a title T3 in the data area of the optical disc. When the title T3 has been recorded, an RSAT that indicates title information of the title T3 is recorded after the title T3. Thereafter, the recording will be repeated in a similar manner.
Next, a description will be given of the reproduction control for the DVD+R optical disc performed by a conventional optical disc recording apparatus.
When a DVD+R optical disc is inserted in the apparatus and loaded therein, the optical disc is detected as a DVD+R optical disc. Then, a list of titles recorded on the optical disc is displayed on a display apparatus as a reproduction list. When the user selects and decides a desired title to be reproduced from among the titles in the reproduction list by operating a remote control unit, the optical disc recording/reproducing apparatus reads out the RSAT for the selected title, analyzes the file system, the control information, and the like, and reproduces the selected title.
The conventional recording/reproducing apparatus records a title on the DVD+R optical disc under the recording control as described above or reproduces a title recorded on the DVD+R optical disc under the reproduction control as described above. However, if the recording of an RSAT for a specific title is failed after the title itself has been  successfully recorded on the DVD optical disc, the specific title certainly can not be reproduced and, further, all RSATs that were recorded prior to the recording of the specific title can not be obtained, thereby making the reproduction of all titles impossible because there is no way to search the locations of the RSATs recorded in the past.
It is to be noted that, when the recording of an RSAT is failed, it is possible to find the RSATs recorded in the past. However, to do so, it is necessary to repeat many times the process of reading out data sequentially in predetermined sector units starting from the inner track side of the optical disc and the process of comparing the data on a sector-by-sector or ECC-by-ECC basis to find if the read-out data is the data of the title information that is searched for. Therefore, an enormous amount of time is required, which makes the reproduction of all titles impossible in reality.
According to a conventional technique described in JP-A-2002-312940, positional information of an area to which data is written is updated and held in a memory every time recording is performed. Also, the positional information held in the memory and the actual positional information of an area of a disc medium on which data is written are compared. When it is determined that the two sets of data are not identical, then the positional information in the memory is recorded to a write-once read-many-times type disc medium, so that recovery is made possible even if recording of the recording management area fails. However, according to this conventional technique, when recording of a specific title on a DVD+R optical disc is completed but recording of the RSAT for this specific title is failed, all RSATs recorded in the past can not be retrieved. In this case, this conventional technique does not solve a problem, i.e., all of the titles can not be reproduced, which is the problem specific to the DVD+R optical disc.
According to a conventional technique described in JP-A-2006-107622, recording zones are sequentially formed from the lead-in area side to the lead-out area side on the DVD-R disc. If an ECC error occurs when video information is recorded in a zone after a completed zone, the readable and normal latest log information selected from between log information 1 and log information 2 is moved to a zone after the last zone.  However, according to this conventional technique, when recording of a specific title on a DVD+R optical disc is completed but recording of the RSAT for the specific title is failed, all RSATs recorded in the past can not be retrieved. In this case, this conventional technique does not solve a problem, i.e., all of the titles can not be reproduced, which is the problem specific to the DVD+R optical disc.